Three species of spiders found in the United States are considered dangerous to humans.
More than 3,000 species of spiders can be found throughout the United States. Only three of these are considered dangerous to humans: recluse, widow and hobo. The brown recluse, black widow and brown widow can be found in Louisiana. These spiders produce venom that can cause serious medical problems. If you think you have been bitten, seek emergency medical treatment.
Southern Black Widow Spider
The southern spider is a small, shiny jet-black spider. The female has a total size of about 1 inch and is a bit larger than the male. The female has the tell-tale red hourglass marking on the underside of her body. Black widow venom contains a neurotoxin that is poisonous to humans. The bite of a black widow is usually painless at first, but an hour or two later pain will begin at the bite site and may travel along nerve routes and down the spine. General symptoms may include nausea, chills, slight fever, elevated blood pressure, burning sensation of the skin, fatigue, uncoordination, breathing difficulty, constipation, muscle aches and abdominal pain. Treatment includes anti-venom along with Benadryl to counteract the allergic reaction, calcium gluconate for muscle cramps and pain relievers. Most symptoms disappear within four days. Death can occur in elderly people and very young children.
Brown Recluse
The brown recluse spider is light tan to dark brown in color with a violin- or fiddle-shaped dark patch on the head. Brown recluse spiders are about 1 1/2 inches in size, with females being a bit larger than males. Brown recluse venom is extremely toxic and contains an enzyme that causes a breakdown of cell membranes and tissues. This leads to necrosis (death) of the skin sourrounding the bite area. Brown recluse venom also causes the victim's body to produce an immune response to the venom. This normal immune response causes the body to release histamines and disease-fighting white blood cells to the area of injury. In severe cases, the immune response can actually create a problem within the immune system, leading to destruction of red blood cells, blood clots, low platelet count, kidney failure and coma. Although extremely rare, death can occur as a result of a bite. Symtoms of a brown recluse spider bite usually occur two to eight hours after a bite. The bite is usually painless, or may feel like a bee sting. Symptoms include severe pain at the bite site after about four hours, severe itching, nausea, vomiting, fever and muscle pain. No antivenom is available in the United States. Treatment consists of pain medications, antibiotics and Benadryl. Severe cases of necrosis may require surgical treatment.
Brown Widow Spider
The brown widow spider is a cousin to the black widow spider. Brown widow spiders are usually found in tropical locations, but according to entomologists with the Louisiana State University Agricultural Center this spider has become increasingly common in Louisiana. The brown widow ranges in color from gray or tan to dark brown and may reach 1 inch to 1 1/2 inches long. The brown widow has a yellow-orange hourglass shape on the underside of the abdomen, as well as white marks on the top of the abdomen. It often has dark bands on its legs. The bite of a brown widow is more toxic than the black widow; however, it does not produce as much venom. It is one of the least aggressive of all the widows, biting only if provoked. The symptoms mimic those of a black widow bite but are usually less severe. Symptoms may include headache, lethargy, profuse sweating, nausea, shortness of breath, muscle cramps and rigidity of the abdomen and legs. Like a black widow bite, the brown widow bite is usually not painful until an hour or two after being bitten.
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